Parkinson's HelpLine

Educational Materials

Science News

Individuals with Parkinsonís Resting Tremor Less Likely to Experience Troubling Levodopa Side Effect

- Sep 20 2011

After long-term treatment with levodopa, some people with Parkinson’s disease (PD) experience jerky, involuntary movements of the arms, legs, or head, a condition known as dyskinesia. While the causes of levodopa-induced dyskinesia (LID) are still unclear, a new study published in the August 2011 issue of Archives of Neurology has revealed that people who have a resting tremor when diagnosed with Parkinson’s are less likely to experience this unpleasant side effect.

For many people with Parkinson’s, the first obvious sign of their disease is a shaking of the hands when the muscles are relaxed and at rest — a so-called resting tremor. Previous research has shown that people with resting tremor often have a different course of Parkinson’s than those who do not. Stefan Kipfer, M.D., of the University of Berne, in Switzerland, wondered if resting tremor could also predict a person’s likelihood of developing LID. To answer this question, Dr. Kipfer and his colleagues analyzed data from 85 people with Parkinson’s who were in the database of the Movement Disorders Center in Berne, Switzerland.

Results

Thirty-nine of the 85 people with Parkinson’s had LID.

People with Parkinson’s with LID had a longer duration of Parkinson’s, a younger age of onset, more axial motor symptoms such as abnormal posture and gait, and were less likely to have resting tremor as a first sign of disease.

The absence of a resting tremor at diagnosis was a strong predictor of LID, independent of daily levodopa dose or duration of Parkinson’s.

What Does it Mean?

Parkinson is a very heterogeneous disease; one in which different people may have different presenting symptoms and different disease course. Resting tremor is perhaps the most recognizable sign of Parkinson’s, yet only about half of all people with Parkinson’s exhibit this symptom at diagnosis. Studies have shown that people who experience resting tremor as an initial sign of Parkinson’s have a slower disease progression and respond differently to therapies than those who do not.

Some people with PD develop LID months or years after treatment begins. Much time and energy is being devoted to finding clinical and biological tools that are able estimate disease progression in different individuals. This retrospective study is part of that effort and suggests that doctors might be able to predict a person’s likelihood of developing LID on the basis of whether or not they have resting tremor as an initial manifestation of their disease. This knowledge could allow doctors to better prepare and monitor individuals with Parkinson’s for the troubling side effect.